Portable electronic devices such as smart telephones, tablet computing devices, and multimedia players are popular. These electronic devices can be used for performing a wide variety of tasks and in some situations, can be worn on the body of a user. As an example, a portable electronic device can be worn on a limb of a user, such as on the wrist, arm, ankle, or leg. Knowing whether the electronic device is worn on the left or right limb can be helpful or necessary information for some portable electronic devices or applications. For example, it can be necessary to know whether the electronic device is worn on a left or right limb when the electronic device includes one or more biometric applications, such as an electrocardiography application or a medical measurement or diagnostic application.